"How do we get an intelligent personal assistant into the home of every Amazon customer?" That simple query, according to sources involved, set the mission for Amazon CEO Jeff Bezos and the team he tasked with creating the e-commerce giant’s latest entry into the hardware market: the Amazon Echo, a $179 cylindrical speaker roughly as tall and sturdy as a bottle of Merlot cut off at the neck. Sure, the Echo, which officially launched this past June, is good at playing music, delivering excellent bass and clear treble. But the key is what’s inside: Alexa, an always-listening Siri for your living room. It’s Amazon’s vision of the platform of the future, one that gives you the ability to control your home by voice.

Alexa is able to control Philips Hue lights and turn on and off appliances plugged into Belkin’s connected outlets. She also works with Garageio’s Wi-Fi-connected garage-door openers and Scout Alarm’s home-security systems.

Say the word Alexa, and the device’s top glows blue, awaiting your command. Like Siri, she can respond to a laundry list of queries and requests—Alexa, how tall is Mount Everest? Alexa, could you set an alarm for tomorrow morning? But whereas Apple designed Siri primarily for mobile consumption through iPhones and iPads—push a button and talk—Alexa is invisible and ever-present, a natural interface for the connected home.

For decades, we’ve heard and seen visions of what the smart home of tomorrow could bring, from HAL 9000 and The Jetsons to Minority Report and Her. But this promise has leaped toward reality in recent years, thanks to improved technology and economic manufacturing, growing venture-capital (and crowdfunded) investments, and a network of so-called Internet of Things devices. Just as they did on PCs and mobile devices before, tech giants are racing to build the next big platform, this time for the connected home, a market poised to grow to $58 billion in the next half-decade.

The domestic arena has tempted tech giants at least as far back as Microsoft’s release of the Xbox console in 2001. But now, rather than only battle to build the connected-TV box that could be a digital hub for the home, these companies have shifted their focus from hardware to voice interfaces, which may be the trick to getting their ecosystems widespread adoption. Apple’s HomeKit platform will enable Siri to control devices such as the window shades and coffeemaker. Google has integrated voice commands into Nest, the smart-home company it spent $3.2 billion to acquire. Microsoft is making its personal assistant, Cortana, a key feature for the Xbox One.

The logical next step is to allow people to shop without having to touch a thing—making the Prime experience even more compelling.

What makes Alexa stand out in this crowded market is that Amazon is already an essential home-management tool for a whole lot of people, especially the estimated 40 million who have signed up for Prime membership. Run out of paper towels, need to replace your smoke detector, or just want to cue up the latest episode of Orphan Black? With its e-commerce reach and growing video ambitions, Amazon is there for you. The logical next step is to allow people to shop without having to touch a thing—making the Prime experience even more compelling.

As the Echo took shape years ago at Amazon’s secretive Lab126, best known for developing the Kindle e-reader, the responsible teams were bullish about the myriad use cases for an ever-listening virtual assistant inside the home: If you’re in the kitchen with hands covered in barbecue sauce, why not have Alexa set a timer for your ribs rather than fiddle with your iPhone? What if she could read you the news as you took your morning shower? Or order an Uber when you’re hurrying to catch your flight? The applications were seemingly limitless.

Perhaps Amazon’s biggest hurdle: Alexa will have to embrace—and be embraced by—some of the company’s main rivals. If products such as Apple TV and Google’s Nest thermostat gain more widespread traction with consumers, Amazon will have to find a way to get them to integrate with Alexa.

Installing connected-home devices can be a costly headache, involving syncing various services over Bluetooth, Wi-Fi, different accounts, and apps. Until these products are easier to use and connect or arrive in prepackaged home kits with installation included, this market will have a hard time breaking through.

For a service that aims to be an assistant in the home, Alexa is still surprisingly stilted in her interactions. To become a true companion, she’ll have to develop better language skills and learn to identify multiple voices—not just a user’s own, but also a spouse’s or child’s—and respond accordingly.

Inevitably, Alexa will live or die based on which services and applications its partners choose to build for the platform. The trick for Amazon will be maintaining quality and valuing convenience over cool. The best applications for Alexa are the ones that are simple, useful, and addictive, like asking for the weather forecast.

But the company was wary of spending resources to solve problems that didn’t exist—or creating new ones. Bezos was personally involved in keeping Alexa’s voice cues simple, to avoid subjecting users to unnecessary and frustrating interactions, such as asking Alexa to turn off a light only to hear, "Which one?" "He was very specific about it," says a former product manager involved with the Echo’s development. "I remember [going over an interaction] in a session with Jeff, and he was just like, ‘This is not going to work. People don’t want to go through all these steps, ’cause it’s annoying.’ " The teams killed a lot of promising applications to streamline the user experience.

When Amazon announced the Echo in late 2014 and then rolled it out to beta testers and the tech media, the reception was mixed. Many felt the product was cool and different—certainly a departure for Amazon­—but they questioned its utility and immediately launched into Siri comparisons. Thus began an inevitable pitting of the two voice assistants against each other in knowledge games, which is a fundamental misunderstanding of Alexa’s mission. Both services have cloud-based "brains" that are constantly updated, in part, through user-generated questions, so it’s no wonder that Siri, several years older than Alexa, is smarter. Furthermore, Alexa was developed for a totally different environment than Siri. When placed in the home, Alexa is a star.

Amazon aggressively added features before the Echo’s launch this year, including the ability to sync with Google Calendar and read books aloud from Audible.com. It also made waves by announcing a $100 million Alexa Fund to attract third-party developers to build on its platform and integrate the voice interface into their software and hardware. Though the list of initial partners was short, it nevertheless offered insight into Amazon’s vision of the connected home. With Scout Alarm, an Internet-connected security system, you can monitor your home right through Alexa; with Orange Chef, a cooking-assistant service, you can ask Alexa for recipes; and with Garageio, a Wi-Fi–connected garage-door opener, you can make sure your car isn’t getting battered by the nor’easter raging outside.

Amazon’s fund seeks to establish what’s missing from current connected-home devices: one service—and one voice—to unite them all. While there have been a slew of promising inventions in recent years that are capable of turning our homes from dumb to smart, these gadgets haven’t actually made our lives easier; instead they’ve left us with an ever-growing number of separate apps, remote controls, and operating systems to monitor. "Alexa removes these barriers and opens up a world of new interactions," says Dave Shapiro, cofounder of Scout Alarm.

Amazon’s fund seeks to establish what’s missing from current connected-home devices: one service—and one voice—to unite them all.

The challenge for Alexa will be remaining agnostic as its ecosystem grows. The fact is, Amazon is no more likely to build a dishwasher than Apple is to create a microwave, so it must rely on third parties like GE and Whirlpool to support its voice service. That means creating a platform so universal that it might even welcome products from competitors like Apple and Google.

As promising as voice technology is as a means of controlling the home, it’s likely only a stepping stone. The real achievement, industry insiders say, will be when Siri or Alexa can learn your patterns well enough to automate these tasks altogether. Which means that the voice interface of the future may be the one that all of our dishwashers, refrigerators, and air conditioners use to speak to each other.

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